An ‘atmospheric river’ storm approaching California Wednesday is expected to soak with potential flooding, bring in high winds and blanket the Sierra Nevada with 2 to 4 feet of snow, according to the National Weather Service. The valley is expected to see up to three inches of rain, with up to six inches in the foothills.

The heaviest rains and possible flooding are expected Wednesday afternoon through Thursday morning, according to the weather service. Based on expected rainfall and wind conditions, with gusts possibly reaching 50 to 60 mph, the storm Wednesday could be the strongest so far this winter.

In the Bay Area, “everyone is going to see the heavy rain associated to this storm. It’s not going to discriminate” to cities that often experience a rain-shadow effect, such as San Jose, said Ryan Walbrun, a meteorologist with the weather service. As much as 6 inches of rain is possible in the coastal mountains, the weather service said.

The storm Wednesday has the “potential” to be the strongest so far this winter, Walbrun said.

“On a statewide basis, from the Oregon border to San Diego, I think everybody is going to benefit from this,” Walbrun said. “A lot of snow will be dropped in the Sierra.

“It’s a pretty big storm, there’s no doubt about it.”

Light to moderate rain will develop along the coastal ranges early Wednesday, with more widespread rain over the North Bay by midday. The system will then move south with increased intensity.

The weather service expects the heavy downpours to cause flooding on roadways during the Wednesday evening commute. There is also a risk of flooding in small streams and creeks, as rainfall rates may reach 1 inch per hour, according to the weather service.

Blizzard conditions are possible Thursday in the Sierra Nevada, where as much as 2 to 4 feet of snow could fall at elevations 7,000 feet and higher, according to the weather service. Below 7,000 feet, 8 to 18 inches of snow is expected, with a potential for as much as 30 inches.

Although the weather service does not predict roadway closures, Walbrun said he would be surprised if Interstate 80 and Highway 50 remain open at pass levels during the height of the storm Thursday. He advised travelers to avoid driving to Lake Tahoe or Reno during the storm.

“This is the type of storm that I would be stunned if there’s not prolonged closures on the interstate,’ Walbrun said.

Active weather returns this week to the Sierra and Western Nevada. Expect major travel impacts Wednesday-Thursday. Blizzard conditions and road closures will be possible at high elevations. If you cannot delay travel over the passes, start making preparations now #CAwx#NVwxpic.twitter.com/vRuvYXx1b4